What are the Best Fish for Aquaponics and Where do I Buy Them?

Aquaponics has become increasingly popular as a growing system in the past 10 years. It combines conventional aquaculture with hydroponics to form a highly sustainable and environmentally responsible method of Agriculture.

Aquaponic systems come with many benefits – very low water consumption as compared to traditional agricultural means, low energy usage, little to no chemical usage, low susceptibility to pests and diseases, and it’s environmentally friendly with no waste or biproduct.

Setting up an aquaponic system comes with its challenges. The four main components – a grow bed, a tank, fish, and plants, should be carefully planned out. The grow bed is used in raising plants in the aquaponic system. The tank is where fish will be kept – you will have to consider the size of the aquaponic system when deciding the size of the tank. Fish play a key role in an aquaponic system, as they will be the source of natural fertilizer for the plants being cultivated. Plants also play a key role, taking up waste left by the fishes and converting them to rich nutrients.

To build a successful aquaponic system, you will also have to carefully select the fish by considering several factors. It is important to plan which types of vegetables you want to grow and pair them with the right type of fish. Certain fish and plants thrive at specific temperatures and pH levels so it is essential to make sure that both plants and fish will be successful in the given water conditions.

In this article, we'll cover:

The best fish for aquaponics: species, and pros and cons

How and where to purchase fish online and what precautions to take when ordering

What factors to consider when selecting fish for your aquaponic system

What Are the Best Species of Fish to Use for My Aquaponics System?

Tilapia originated in the wild in Africa and in the Nile River Basin of Lower Egypt and are considered to be one of the oldest farmed fish on the planet. Among the most popular species for an aquaponics system especially for beginners, it has also taken third place as one of the most important fish in aqua-culture, after carp and salmon. Their high protein content, large size, rapid growth and palatability have made them favorable. Tilapia are also one of the easiest and most profitable fish to far due to their omnivorous diet, tolerance of high stocking densities and rapid growth. They prefer water with a pH level between 7-8.

The Nile Tilapia and Mozambique Tilapia are two of the most favored types of Tilapia due to their fast growth rate and late breeding stage.

Tilapia are durable fish that are resistant to parasites and diseases making them an excellent fish for beginners. They can also tolerate wider range of water quality and temperature changes. They thrive in water temperatures between 70-80 degrees F and are usually kept at around 73 degrees to accommodate the plants. They're easy to breed and grow quite quickly – up to 2.5 lbs. in 7 months.

One thing to consider is that Tilapia can breed almost too efficiently – spawning every 4-6 weeks so a second tank might be helpful in containing the babies.

Tilapia can be quite costly to maintain as famers need an energy source to maintain a tropical temperature range in their tanks as they require warm water.

Perch are a great choice for aquaponic system because of their taste, hardiness, growth rate and nutrition. Perch are better at retaining omega 3 than any other fish when fed with feeds high in omega-3 oils. Perch will not breed in captivity, but they have a fast growth rate.

There are three main perch species: the European Perch – found in Europe and Asia, the Balkhash perch – found in Kazakhstan, Uzbekistan, and China, and the yellow perch – found in the US and Canada.

The yellow perch, in particular, are best for aquaponics due to their moderate temperature range and wide pH range. Thriving in temperatures between 67 and 77 degrees F, these carnivorous fish typically reach about 15 inches in size and 2.2 lbs. in weight.

They have the widest pH range of 6.5 and 8.5 among the aquaponic fish species. Perch only breed once a year and require and sudden change in temperature from cold to warm – as to simulate the change from winter to spring.

Trout are closely related to salmon and char and are one of the most widely farmed fish in the world due to them being fairly easy to culture. Most trout live in freshwater lakes and rivers, while others live out their live out their lives in fresh water or spend two or three years at sea before returning to fresh water to spawn. They generally feed on other fish, and soft bodied aquatic invertebrates such as flies and dragonflies. They may also feed on shrimp and small animal parts. Unlike tilapia, trout will not handle dirty water.

Trout are somewhat bony, but the flesh is generally considered to be tasty. The flavor of the flesh is heavily influenced by the diet of the fish.

Among the three most common types of trout – brown, rainbow, and brook – rainbow trout make the best species for aquaponics due to their hardiness. Rainbow trout can withstand the varying conditions an aquaponics system will present.

They are considered a cold water fish and thrive in temperatures between 55 and 65 degrees F. They require a pH range between 6.7 and 7.7.

Trout can grow to about 15 inches in 9 months but require a large lank for them to grow in. Also, they require an oxygen saturation of at least 5.5mg/L. Stocking density is something to pay close attention to so as to make sure that there's adequate oxygen for all the fish.

Bass, a popular American game fish, are very hardy and can tolerate low water temperatures. Bass eat worms, insects, larvae as well as high protein pellets. They prefer to feed on food that stays in the surface or that sinks slowly, rather than to feed off the bottom of the tank.

There are many species of Bass to choose from. These are among the most popular for aquaponics:

Hybrid striped bass which are well suited to aquaponics as they are hardy and resilient to extremes of temperatures and to low dissolved oxygen.

Smallmouth bass which are carnivorous and eat crayfish, insects and smaller fish. They can tolerate cool water but are reluctant to eat pelleted food

Largemouth bass – The northern strain and the Florida strain is generally larger and lives much longer.

Australian bass which are small to medium sized. They feed on insects, or on protein rich pellets.

Though not considered a beginner species for aquaponics by any means, Largemouth bass are widely used in aquaponics systems due to their potential for growth. A full sized adult largemouth bass can reach 12 lbs. in weight in 16 months.

Largemouth bass do not like bright light. They require a strict feeding regime of small shrimp and insects as a baby and then snails and crayfish as an adult. They require a steady water temperature between 65 to 75 degrees and prefer a pH level of 6.5 to 8.5.

Though much maintenance is require for largemouth bass, their size and hearty meat provide a very rewarding harvest.

Catfish are one of the most farmed types of fish and are sought after for their taste - their meat is consumed as a delicacy around the world. Catfish are omnivorous bottom feeders and valuable scavengers. As they are a strong fish, they can withstand a wide range of water conditions. They are not territorial and can tolerate a higher stocking density. Catfish are easy to breed and grow, and within 3 months can be harvested for cooking.

Catfish thrive in a similar temperature range as tilapia at 75 to 85 degrees F and have a pH range of 7 to 8. They grow fast and can reach 2-3 lbs. in 12 months.

Barramundi is an excellent table fish highly regarded in most restaurants and a great fish for Aquaponics, but it is not recommended for beginners. They prefer warm water are reputed to be fast growers.

However, they are hard to grow as Barramundi fingerlings need to be graded to survive. The fingerlings attack and eat one another – the larger sized fish will nip and wound the smaller fish. The wounded smaller fish will eventually die if not eaten by the others. Barramundi need lots of dissolved oxygen going into their tank and they need very good quality water.

Barramundi thrive at a specific range of 77 to 86 degrees F and a pH range of 6.5 to 7.2.

Despite the specific conditions and amount of care necessary for successful farming, Barramundi have one of the fastest growth rates among fish in an aquaponic system and are harvestable at 1 lb. in a 6 month period. They have a highly prized meat which is extremely nutritious and high in Omega fatty acids.

Carp are a species of oily freshwater fish, native to Asia. Various species of carp can be reared as food. They are omnivorous and can feed on algae, plants, insects and many other soft bodied aquatic invertebrates. Carp have good reproductive capabilities and can easily adapt in various environments.

Over the past few year, the demand for carp in Western Europe has declined as more desirable table fishes, trout and salmon, have become more available through extensive farming. Nevertheless, Carp make a good species for aquaponics due to their resilience to changes in water conditions.

They have a temperature range of 80 to 82 degrees F and a pH range of 7.5 to 8.0.

Koi are one of the most popular fish used in aquaponics. They have a long lifespan and can easily live and breed within the aquaponic system. Koi are also fairly disease and parasite resistant. They are omnivores and can eat just about any food. As they eat algae, debris and plant matter that fall into their pond, additional feeding may not be necessary. Waste production will have to be monitored and a large and more efficient filter may need to be installed.

Koi are not considered to be a good fish for eating, so you will have to seek alternatives. They thrive in temperatures of 65 to 78 degrees F and pH levels of 6.5 to 8.0.

They are highly successful among beginners due to their adaptability and resilience.

Goldfish are an ideal aquaponics fish as they produce and eat a large amount of excretion, thus providing plenty of nitrates for the plants. They are also hardy, depending on which species you select. However, rapid changes in temperature can be fatal.

There are generally two types of goldfish – twin-tailed and single-tailed. Be mindful to avoid mixing these two species together as twin-tailed fish could end up suffering greatly. As single-tailed gold fish have slim bodies, and are more aggressive and faster swimmers, twin-tailed gold find it hard to compete with them.

Goldfish are inedible ornamental fish and thrive in temperatures of 65 to 78 degrees F and pH levels of 6.5 to 8.0.

How and Where to Purchase Fish Online

Online transactions have revolutionized how we purchase items and live fish are no exception. Yes, it is possible to have live fish shipped to your door by a reputable company via expedited shipping and proper packaging. Here are some tips in ensuring you have a hassle-free buying experience.

Select a Reputable Vendor - Be sure to read the reviews posted by other customers and ensure that the vendor is reliable in their packaging and delivery of the live fish. Make sure the fish they are selling are healthy and well.

Look for Guarantee - Only purchase from stores that offer a guarantee that their fish will arrive alive and will offer a refund for any other outcome.

Expedited Shipping Only - Most reputable online fish vendors will only sell ship the fish under expedited or next day service due to the time-sensitive packaging, but it doesn't hurt to double check for it.

Be Home When it Arrives - Expedited shipping is great in ensuring that it arrives at your doorstep on time but it doesn't help if the package is sitting on your front porch while you're on vacation. Be sure that someone is home to place the fish in their proper conditions right away to ensure optimum health.

Reputable Online Stores

What to Consider When Choosing Fish Species for Your Aquaponic System

Ornamental vs Edible Fish

Your choices of fish will depend on whether you want to eat them. As the name suggests, you should choose edible fish if you’re looking to grow fish that you can eat.

The inedible fishes – Koi and Goldfish – do have their own benefits. Goldfish, while slightly more difficult to maintain than Koi, are much less expensive and can be used for smaller aquaponics systems or trial runs. Koi fish are great for beginner systems as they're quite resilient to the volatility a a new aquaponics system can present. They're also very resistant to diseases and parasites, two things that can turn a well-maintained aquaponic system upside-down.

Edible fishes have the obvious benefit and the larger, faster-growing fish come with their own special conditions and requirements.

Breeding, growth rate, and stocking density

Breeding is a factor to consider when purchasing fish and when considering the type of system set-up as a whole. Some species don’t reproduce easily in a controlled tank which can be frustrating, especially for beginners. Others, such as Tilapia and Catfish breed quite quickly, which can also lead to complications if the system isn't built properly for it.

Spawning vs Livebearing - There are two main methods fish use for breeding – spawning and live-bearing. Most fish spawn, whereas a fair number of fish are livebearers. Spawning involves reproducing freely by laying eggs when special conditions, known as spawning triggers, are met. Live-bearing involves retaining eggs inside the body and live birth to free-swimming young. Livebearers are generally preferred for fish-breeding. Live-bearing aquarium fish, often simply called livebearers, are fish that retain the eggs inside the body and give birth to live, free-swimming young.

Growth Rate - The growth rates of fish vary. With your aquaponic system, it is better to have fish with a range of growth rates to harvest fish regularly over a long period of time. The range of fish growth rates vary. It is also important to consider the time of year at which the fish are ready to be harvested. Overcrowding is an issue that needs to be addressed as we'll see in the next section.

Population Density - You will have to stock your tank in with a reasonable number of fish, keeping in mind the growth rate of the fish, the available space in the tank and your budget for purchase and maintenance. The size your fish could grow up to should also be kept in mind when considering the available space. An overcrowded fish tank can disrupt the oxygen and ammonia levels in the water, as can an underpopulated tank. Keep population density in mind when harvesting fish as well.

Fish Diet

In terms of diet, fish can be classified into three main categories – herbivore, carnivore or omnivore. Fish suitable for aquaponic systems are either carnivore or omnivore.

Carnivores require a high protein diet which can be difficult to achieve without purchasing high-quality commercial feed specifically formulated for carnivorous fish. Some carnivorous fish may prefer to feed on other fishes instead, especially the young and weak. So generally, carnivores cannot be mixed with other species and they should all be of approximately same sizes to prevent them from snacking on each other.

Omnivores can coexist with their own species and with other omnivorous fish species, so they are an excellent choice for a community tank. Omnivores are also known to be the easiest to feed.

Maintenance difficulty

You will need to maintain your aquaponic system by testing the water, changing the water and checking your equipment, but your fish will also need some maintenance. Some fish are difficult to care for whereas others are relatively easier. Your fish may fall ill or experience bullying, resulting in you having to administer medication to your fish or put your fish in isolation.

Temperature

Fish are cold-blooded animals – they take on the temperature of the water in which they live in, so temperature plays a very important role. The water temperature requirements of fish depend on their natural climate.

For example, fish originating in the lake waters of Africa such as tilapia have evolved to thrive in warm water (above 70oF), whereas fish originating in streams of North America such as trout have evolved to thrive in cold water (55oF and below). So, when choosing your fish, you should be mindful about what water temperature you will be able to provide.

The fish and plants you select for your aquaponic system should also have similar needs in terms of temperature. The closer they match, the higher the chances of success of your aquaponic system.

PH Sensitivity

The pH control of your aquaponic system is essential for the health of your fish. An inappropriate pH level can cause poor fish growth and may lead to death of your fish. So, you need to know what result in high pH or low pH levels in your aquaponic system, and how you can balance the levels within the appropriate range.

It is important to match the pH of water in the fish that with that in the fish bag when you are introducing new fish into your system. The difference between the pH values should not be greater than 0.2. As with temperature, the fish and plants you select for your aquaponic system should have similar needs in terms of PH Sensitivity. This improves your chances of success as well.

Conclusion

For a successful aquaponics system, it is important to choose the right fish, but it is also essential to establish a maintenance routine, especially for an outdoor setup. Make sure to regularly test the water for pH, ammonia level, and temperature. Regular testing will help you notice variations that could be problematic before they harm your fish or plants. Frequently draining some water and adding fresh water will also help keep things balanced. Cleaning on a routine basis will help prevent algae overgrowth.

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